At a trade show I talked with a supplier of Food Grade Mineral Oil. His
comments were interesting. First, he said  FGMO is about 3-5 times more
expensive than Pharmaceutical grade MO.  Bulk PGMO is about 1.50 a
gallon. The only difference is FGMO is fabricated in "clean rooms", but
it is the same stuff as PGMO.
He asked how we were going to use it- told him in the hive. He asked why
we needed FGMO vrs PGMO when we were going to use it in a totally
unclean environment, the inside of a hive. I could not really answer
that. (By the way, PGMO is the MO we use for making beeswax hand cream.
So it is OK for putting on your hands... which touch food, but not OK
for the inside of a hive, which few of us will be gnawing on.)
If the rational is that we do not want to be accused of putting an
unclean substance in our hives, then we should start sterilizing hive
tools.
I think we may be in overkill with FGMO when PGMO is as good and has no
health risk and is much cheaper.
Plus, you know that many beekeepers will use PGMO because it is cheaper
and there is no way to tell the difference after it is in the hive.
Would appreciate your comments, thoughts.
Bill Truesdell
Bath, ME